Which of the following is a step in the initial treatment of hyperkalemia?

• A. IV Calcium chloride
• B. Insulin + glucose
• C. IV Calcium gluconate
• D. Kayexalate

Answer: (C)

The important idea here is to protect the heart first when hyperkalemia is present. High potassium makes heart cells more excitable and can lead to dangerous arrhythmias, so the immediate move is to stabilize the cardiac membrane. IV calcium does exactly that: it raises the threshold for depolarization and decreases the membrane’s responsiveness to the elevated external potassium, buying time to lower potassium levels without waiting for other treatments to take effect. Calcium gluconate is preferred for peripheral IV use because it provides this stabilizing effect with a lower risk of vein irritation compared to calcium chloride, which is more caustic if extravasation occurs. After the heart is stabilized, you then shift potassium into cells (for example, insulin with glucose) and remove it from the body (diuretics, resin therapy like Kayexalate, or dialysis as needed). So the initial step is IV calcium gluconate to protect the myocardium while more definitive potassium-lowering measures are implemented.